Due to the increasingly strict regulations on energy saving and environmental protection, the development direction of the automobile industry in recent years has been to develop vehicles with low fuel consumption and low emissions. Among the various measures to reduce fuel consumption, the realization of lightweight vehicles is the first measure, and the main focus of lightweighting is set on the walking system.
To this end, efforts to use light metal materials (aluminum, magnesium) and organic materials (polymer materials) in the walking system have become effective measures to reduce the quality of empty cars.
The use of aluminum as a light structural material is increasing. At present, the average aluminum consumption of each car is 70 kg, accounting for about 6% of the empty car mass. Among them, the aluminum consumption of the engine and transmission is 40 kg, the travel system is 18 kg, the body is 10 kg, and the amount of equipment in the car is 3 kg. According to the latest estimates, the amount of aluminum used in cars will reach 120 kg in recent years.
So far, automobile light metal materials are mainly concentrated on the body, and the amount of rotating parts and vibrating parts is also increasing day by day, and the wheels occupy the first place by mass. By adopting lead wheels, not only can the energy consumption during acceleration of the car be reduced, but also the small tangential force of the wheel connected to the suspension of the body can be achieved. This is beneficial to the size design and quality of the body and walking system. The reduced non-built mass due to the use of aluminum wheels also incidentally improves the driving performance and driving comfort of the car.
Aluminum wheels have been used for 20 years and have an impact on motorsports. In 1923, the car made by Pujachi was equipped with aluminum wheels cast by sand moulds. Since then, the German Mercedes-Benz Company has spent three years developing the spoke-type aluminum wheels with aluminum alloy wheels and gold wheels. The wheels are extruded and the aluminum wheels are only used for racing.
Today, aluminum wheels have become original or optional parts in automobile production plants. Car wheels are mainly manufactured by low-pressure casting. Since the mid-1960s, there has been a marked increase in the use of forged aluminum wheels for cars and trucks. In particular, it is worth noting that the aluminum forging technology developed by Otto Fuchs has been put into mass production and has been applied. On Mercedes-Benz and Borscher cars.
The successful use of aluminum wheels is first of all because it is lighter than steel wheels and can meet its demanding design requirements. In addition, due to the higher thermal conductivity of aluminum, it can quickly dissipate the frictional heat of the tire. As a result, on one hand, the thermal load of the braking device can be reduced, and at the same time, the driving safety of the car can be improved. Furthermore, the use of aluminum wheels will reduce the heating of the tire, that is, reduce the tire's extrusion work. Therefore, it is helpful to reduce the wear of the tire.
The requirements of modern automobiles for wheel systems are as follows: minimum mass, good static and dynamic strength characteristics, good corrosion resistance, good rotation characteristics, good thermal conductivity, good regeneration performance, unrestricted forming Possibility, excellent surface finish, low price.
The determination of the size of the car wheel should not only be based on the requirements of the car under normal driving conditions, but also consider the use requirements in the wrong use state and overloaded working stress, MPa conditions, especially at high speed under low gas pressure. Requirements under poor driving conditions. In order to develop a wheel that is as light as possible, it is necessary not only to choose low-density materials, but also to perform material performance tests. While having high static strength, it must also have good plasticity so that it can be used under overload conditions. Load through deformation. In addition, it must have good vibration resistance and corrosion resistance to achieve the necessary service life.